When No-Reference Image Quality Models Meet MAP Estimation in Diffusion Latents

Fuente: arXiv
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Hauptverfasser: Zhang, Weixia, Li, Dingquan, Zhai, Guangtao, Yang, Xiaokang, Ma, Kede
Format: Preprint
Veröffentlicht: 2024
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author Zhang, Weixia
Li, Dingquan
Zhai, Guangtao
Yang, Xiaokang
Ma, Kede
author_facet Zhang, Weixia
Li, Dingquan
Zhai, Guangtao
Yang, Xiaokang
Ma, Kede
contents Contemporary no-reference image quality assessment (NR-IQA) models can effectively quantify perceived image quality, often achieving strong correlations with human perceptual scores on standard IQA benchmarks. Yet, limited efforts have been devoted to treating NR-IQA models as natural image priors for real-world image enhancement, and consequently comparing them from a perceptual optimization standpoint. In this work, we show -- for the first time -- that NR-IQA models can be plugged into the maximum a posteriori (MAP) estimation framework for image enhancement. This is achieved by performing gradient ascent in the diffusion latent space rather than in the raw pixel domain, leveraging a pretrained differentiable and bijective diffusion process. Likely, different NR-IQA models lead to different enhanced outputs, which in turn provides a new computational means of comparing them. Unlike conventional correlation-based measures, our comparison method offers complementary insights into the respective strengths and weaknesses of the competing NR-IQA models in perceptual optimization scenarios. Additionally, we aim to improve the best-performing NR-IQA model in diffusion latent MAP estimation by incorporating the advantages of other top-performing methods. The resulting model delivers noticeably better results in enhancing real-world images afflicted by unknown and complex distortions, all preserving a high degree of image fidelity.
format Preprint
id arxiv_https___arxiv_org_abs_2403_06406
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle When No-Reference Image Quality Models Meet MAP Estimation in Diffusion Latents
Zhang, Weixia
Li, Dingquan
Zhai, Guangtao
Yang, Xiaokang
Ma, Kede
Computer Vision and Pattern Recognition
Contemporary no-reference image quality assessment (NR-IQA) models can effectively quantify perceived image quality, often achieving strong correlations with human perceptual scores on standard IQA benchmarks. Yet, limited efforts have been devoted to treating NR-IQA models as natural image priors for real-world image enhancement, and consequently comparing them from a perceptual optimization standpoint. In this work, we show -- for the first time -- that NR-IQA models can be plugged into the maximum a posteriori (MAP) estimation framework for image enhancement. This is achieved by performing gradient ascent in the diffusion latent space rather than in the raw pixel domain, leveraging a pretrained differentiable and bijective diffusion process. Likely, different NR-IQA models lead to different enhanced outputs, which in turn provides a new computational means of comparing them. Unlike conventional correlation-based measures, our comparison method offers complementary insights into the respective strengths and weaknesses of the competing NR-IQA models in perceptual optimization scenarios. Additionally, we aim to improve the best-performing NR-IQA model in diffusion latent MAP estimation by incorporating the advantages of other top-performing methods. The resulting model delivers noticeably better results in enhancing real-world images afflicted by unknown and complex distortions, all preserving a high degree of image fidelity.
title When No-Reference Image Quality Models Meet MAP Estimation in Diffusion Latents
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2403.06406